Driving circuit of switching power supply field effect tube

Driving circuit schematic diagram:

Driving circuit of switching power supply:

　　

The main function of the drive circuit is to amplify the variable width pulse output by the pulse width controller as a drive signal for the high-voltage power switch device. The drive circuit generally has an isolation function. Transformer coupling is often used to achieve the excitation of the high-voltage power switch device and the isolation between the input stage and the output stage. At the same time, it also applies a reverse bias to the power switch device when it is turned off to accelerate the shutdown of the device. When driving MOSFET devices, the conventional drive circuit is implemented with a drive transformer. Considering the leakage inductance and lead inductance of the drive transformer, it is difficult for the main MOSFET with a large Cg-s to charge and discharge at high speed. Therefore, the usual way is to use the drive transformer to drive a totem drive circuit of a MOSFET with a smaller Cg-S, and then drive the main MOSFET by this circuit. As shown in the figure, the primary coil input signal of the drive transformer is the output drive signal of the control circuit, which is output after being isolated by the transformer and shaped by the shaping circuit. The transformer plays an isolation role. The optocoupler has both isolation and anti-interference functions. After shaping, it drives the main MOSFET tube through the totem drive circuit.